land-speed
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Re: hardness/Cof salt test

To: land-speed@autox.team.net
Subject: Re: hardness/Cof salt test
From: John Goodman <ggl205@yahoo.com>
Date: Sat, 16 Aug 2003 12:42:31 -0700 (PDT)
Mayf, I am as open with sharing information as one can
get. If I have something to share or if asked about
something I believe I know, I will share it.  

"Traction is traction, but I suspect the data base
from which those methods are derived is a tad
different, asphalt vs salt namely."

Yes, that's true. It gets more convoluted when you
consider the different types of differentials
available. Add to this the need for corner grip and
some separation between LSR on salt and road racing on
asphalt, becomes wider. Still, we are talking about
wheel spin (Cf) and what has to be done to minimize
it. 

"I aim on taking data from one location through out
the day in increments of one hour or so."

This makes some sense. It should give a general
understanding about how and to what degree salt
changes over time. If possible, could you take another
sample, at roughly the same time, about two miles
farther up? It would be nifty to see how the two
samples correlate. Wish I could be there to help with
this. Sounds like fun. 

"As to publishing not everyone has their own web
site,> your sensitivities must have let you down:"

You are probably right about that. Also, my crack
about you being a meatball. It may or may not be true
but I had no right to say it. My apologies. I was
having a really pissy day yesterday. 

"How can we weigh the drive wheels cheaply.."

The cheapest and best strain gage I have seen is a
simple lever arrangement. It is nothing more than a
vertical piece of 1 1/2" round steel tubing with
another piece inside capable of sliding. A horizontal
lever (of known length) is attached to a scale (meter)
which contacts the wheel. Another lever, also of known
length, pivots on the outer vertical tubing, causing
the horizontal lever to lift the wheel (corner). As
the wheel moves up, the meter reads the force required
and a corner weight can be determined. These things
used to sell commercially for around $150. I haven't
seen one in years but look easy to make.

I still like the idea of testing the car against
whatever surface conditions are for the moment. Data
generated via data acquisition systems have always
worked well for me. I am about to do this on my salt
car going forward. What will be of great help is
correlative data you generate from two individual
sites. If data correlates with significance, one may
determine changes required from a baseline established
on data acquisition. Here is the real value I see in
your testing of salt conditions.

John Goodman

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